Platinum nanoparticles obtained on S-layer protein/polymer particle systems and their performance as catalysts

HUGGIAS S; BOLLA PA; SERRADELL MA; CASELLA ML; PERUZZO PJ

Mar del Plata

Congreso; XVI SIMPOSIO LATINOAMERICANO DE POLÍMEROS Y XIV CONGRESO IBEROAMERICANO DE POLÍMEROS; 2018

INTEMA, UNMdP

The adsorption of proteins in polymeric particles has significant importance in various applications1. Among them, its use as a support for nanocatalysts based onprecious metals is a promising field2. In particular, the S-layer proteins (bacterial surface proteins) have been used as a biotemplate to obtain metal arrangements with precise spatial distribution due to the regular paracrystalline structure that they can adopt. With this in mind, this work presents the synthesis of Pt nanoparticles on polymer particle/S-layer protein systems and their performance as catalysts.The S-layer protein was obtained from the strains L. kefiri CIDCA 8348 and L. kefiri CIDCA 831113. The polyacrylic (AC) and polyurethane (PU) particle´saqueous dispersions were obtained by emulsion polymerization and by the prepolymer method respectively, and then characterized as previouslyreported4. The adsorption of the proteins on the polymers was carried out by combining the aqueous dispersions of both components in different ratios. Thesystems were isolated from the free protein by centrifugation and separation of the supernatant. Then, they were incubated in (NH4)2PtCl4 solution, thenon-adsorpted complex was removed, and the resuspended pellet was reduced with H2 at mild conditions. The samples were characterized by FTIR, SAXS and TEM to evaluate the morphology. The catalysts were evaluated by following the reduction of p-nitrophenol with NaBH4 by UV-Vis spectroscopy.FTIR spectra of the protein/polymer supports showed the contribution of the typical bands of both components, with changes in the Amide II band of theproteins due to the interaction of both materials. The SAXS spectra showed contributions consistent with the formation of a protein corona around the polymer particle. After reduction, strawberry-like particles wereobtained where platinum nanoparticles of around 5 nm in diameter located on the surface of the polymer-protein systems were observed by TEM. Thecatalysts showed conversions between 90 and 100% for reaction times of 60 to 90 min in the reduction of p-nitrophenol with NaBH4.Based on the capacity of the S-layer proteins to act as a biotemplate for metal clusters, it was possible to obtain Pt nanoparticles/protein-polymer composites at mild conditions. These catalysts were active for the reduction of p-nitrophenol in the presence of NaBH4, with high conversion percentages.